Full text article. Also available at https://doi.org/10.1093/tropej/fmx109Childhood diarrhoea is a global public health problem especially in unplanned settlements of low- and middle-income countries. Different studies have associated household settlement and childhood diarrhoea, but the prevalence and risk factors associated with childhood diarrhoea at the community level are not clearly known. A community-based cross-sectional study was performed to determine the prevalence and risk factors associated with diarrhoea in among 480 children between 6 and 59months of age in Mwanza city from June to August 2016. Risk factors associated with childhood diarrhoea in Mwanza city were determined using univariate, bivariate and multivariate analysis. The study showed a prevalence of diarrhoea of 20.4% and an association between type of settlement and childhood diarrhoea (p<0.001) in a chi-square analysis. During bivariate analysis, and logistic regression, after controlling for other factors, unplanned settlement was significantly associated with childhood diarrhoea (odds ratio¼3.475, p<0.001 and AOR¼3.469, p<0.001). Other factors associated with childhood diarrhoea were behaviour of mother washing hands before preparing food (AOR¼0, 193, p<0.001), mother washing hands after changing child’s napkins (AOR¼0.544, p<0.036) and the behaviour of the child washing hands after toilet (AOR¼0.447, p<0.006). Risk factors associated with childhood diarrhoea in Mwanza city are unplanned settlement and behaviour of mother and child washing hands during critical time; hence, continuous community health promotion insisting on washing hands with soap and water during critically time is the best method for fighting childhood diarrhoea in Mwanza city.